1. Field of the Invention
The invention concerns a calorimetry process for determining the quantity of thermal energy given out or taken up by a sample during an isothermal change of physico-chemical state, and is also concerned with a calorimeter for carrying out said process.
2. Description of the Prior Art
To measure the quantity of thermal energy given out or taken up by a sample during an isothermal change of state, the quantity of thermal energy which has to be fed to the sample or extracted from it to keep it at the same temperature during the change of state is measured. This is done by placing the sample in a calorimeter, i.e. an adiabatic enclosure. It is customary to determine the quantity of energy exchanged with the sample and the temperature of the sample by electrical means. It is difficult to obtain precise measurements of the amount of thermal energy which has to be extracted if electrical means are used, so that isothermal calorimetry is generally limited to measurements in respect of endothermic changes of state.